It is known to add perfluoropolyether (“PFPE”) polymer as an additive to certain polymers (e.g., thermoplastic polymers) to provide improved properties, such as to reduce the friction coefficient and wear rate of the polymer. However, due to the relatively high cost of PFPE, it is economically feasible to add only small amounts of PFPE to the polymer. For example, it may be possible to add only about 0.1 weight percent of PFPE (based on the total weight of the PFPE and the polymer) to the polymer in order to produce an economically attractive product.
Further problems arise when using such small amounts of PFPE since it is difficult to homogeneously dose and disperse the PFPE in standard processing equipment, such as melt compounding equipment.
Polytetrafluoroethylene (“PTFE”) powder is a commonly used additive to improve friction coefficient and wear rate of certain molded or extruded polymer parts. A problem with using PTFE powder is that relatively high concentrations (above 5 weight percent) generally are needed to obtain significant, desired effects. Moreover, the addition of PTFE powder in high amounts will generally reduce certain mechanical properties of the modified polymer, such as impact and tensile strength.
It is also known to add small amounts of PTFE powder to PFPE oil in order to thicken the PFPE oil. Generally, such PTFE containing PFPE oils may contain from about 1 weight percent to about 40 weight percent PTFE powder.